Venoms and venom-derived compounds constitute a rich and largely unexplored source of potentially therapeutic compounds. To facilitate biomedical research, it is necessary to design a robust informatics infrastructure that will allow semantic computation of venom concepts in a standardized, consistent manner. We have designed an ontology of venom-related concepts - named Venom Ontology - that reuses an existing public data source: UniProt's Tox-Prot database. In addition to describing the ontology and its construction, we have performed three separate case studies demonstrating its utility: (1) An exploration of venom peptide similarity networks within specific genera; (2) A broad overview of the distribution of available data among common taxonomic groups spanning the known tree of life; and (3) An analysis of the distribution of venom complexity across those same taxonomic groups. Venom Ontology is publicly available on BioPortal at http://bioportal.bioontology.org/ontologies/CU-VO.